One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,3)(4,6,8,7)(9,10)(11,14)(12,19)(13,16)(15,20)(17,21)(18,24)(22,23)(25,26)(27,32)(28,36)(29,30)(31,35)(33,39)(34,40)(37,38)(2,3)(6,7)(11,17)(14,21)(18,23)(22,24)(25,27)(26,32)(28,29)(30,36)(31,37)(33,40)(34,39)(35,38) involution — undirected(9,10,13,16)(11,14,17,21)(12,15,20,19)(18,22,23,24)(25,28,31,39)(26,33,35,36)(27,34,37,29)(30,38,40,32)(9,10)(11,14)(12,15)(13,16)(17,21)(18,22)(19,20)(23,24)(25,28)(26,33)(27,29)(30,38)(31,39)(32,40)(34,37)(35,36) involution — undirected(1,3,5,2)(4,6,8,7)(9,11)(10,14)(12,18)(13,17)(15,22)(16,21)(19,24)(20,23)(25,29)(26,30)(27,28)(31,34)(32,36)(33,38)(35,40)(37,39)(1,4,5,8)(2,6,3,7)(9,12)(10,15)(11,18)(13,20)(14,22)(16,19)(17,23)(21,24)(25,30)(26,34)(27,36)(28,38)(29,35)(31,40)(32,39)(33,37)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.